The present invention relates to drill bits and, in particular, to a drill bit which can drill along an arcuate path.
There are many situations in the building industry which require holes to be drilled through two perpendicular faces of a board to form a continuous path. This is particularly useful for installing electric wiring which needs to be fed from an inside wall up into an attic, and so forth.
Until now, the way a builder would handle such a situation is that a straight hole would be drilled in from each face and, hopefully, the two holes would intersect. This requires very precise drilling and measurement. If one hole extends beyond the intersection, the wire will tend to go down that extension and get stuck. Even if a perfect L-shaped hole is formed, the wire may get stuck, since there is nothing to urge it along a gradual bending path.
There is a drill bit in Europe, as described in European Patent Publication EP 0181841, which can start at one face and cut along an arcuate path until it comes out through a perpendicular face. This comes closer to meeting the needs of the builder. However, there are several problems with this bit. The first is that it is very complicated, with several cutting edges, each requiring a separate grinding operation--about 15 grinding operations in all. This makes the bit extremely expensive to manufacture, which is probably why it has not yet made its way to the United States. In addition, this bit cuts a very jagged-edged hole, providing numerous places for wires to get caught.